The article shows how to create a simple vtk render window project and show it in the web browser. We need emscripten tool and the visualization toolkit installed. emscripten : https://emscripten.org/docs/getting_started/downloads.html VTK: https://vtk.org/ Build the VTK source to get JS library before our coding. This example uses C plus plus Read more…
I found a bug when we do matrix inverse calculation by vtkTransform object. The version 8.2.0 and 9.1.0 of VTK has the same potential risk in vtkMatrix4x4::Invert(const double inElements[16], double outElements[16]).Let’s see the source code, it judges whether the determinant value is zero by ==. The equal comparison operation for Read more…
We had used vtkImplicitPolyDataDistance to calculate the distance from a point to the target points set in the post Calculate Distance From A Point To PolyData In VTK. We will try a new way using KD-Tree to find the closest point to the test point. The following example puts a Read more…
We had introduced a way to keep a few special models awalys on the top layer in 3D scene. The relative post: https://www.weiy.city/2020/03/make-model-always-on-top/. But it will fail to shift polygons, lines, and points sometimes, eg. when we are in the WebAssembly environment (wasm) for web page.Let’s use an another method Read more…
The post shows a way to move 3D model to the original point in world coordinate system. The file CMakeLists.txt is similar to https://www.weiy.city/2021/12/find-closest-plane-between-points-in-3d-by-covariance-matrix/. The included file point.hpp can be found in https://www.weiy.city/2020/09/project-point-on-line-and-plane-by-special-direction/. #include <iostream> #include <vtkPolyData.h> #include <vtkActor.h> #include <vtkTransformFilter.h> #include “./point.hpp” #include <vtkTransform.h> #include <vtkSTLReader.h> #include <vtkSTLWriter.h> #define Read more…
I want to find the central point, not mass center, between a few points like the following image. The points are on the same plane. Find the longest axis and the orthogonal axis for the points set firstly. Compute the positive farthest point and negative farthest point for every axis. Read more…
Open File By Browser The FileReader object lets web applications asynchronously read the contents of file. You can feel the effect at: https://www.weiy.city/web-test/open-file/ <!doctype html> <html lang=”en”> <head> <title>Test</title> </head> <body> <input type=”file” id=”file-input” /> <h3>Contents of the file:</h3> <pre id=”file-content”></pre> <script> function displayContents(contents) { var element = document.getElementById(‘file-content’); element.textContent Read more…
The post shows a way to calculate unsigned distance Between Two 3D Models. The models can’t have too low resolution because the result that vtkDistancePolyDataFilter computes will not be accurate. #include <vtkActor.h> #include <vtkCleanPolyData.h> #include <vtkDistancePolyDataFilter.h> #include <vtkNamedColors.h> #include <vtkNew.h> #include <vtkPointData.h> #include <vtkPolyDataMapper.h> #include <vtkPolyDataReader.h> #include <vtkProperty.h> #include <vtkRenderWindow.h> Read more…
I found a new way to make interpolation spline curve smoother. Let’s explore it based on the previous post, VTK – Make Interpolation Spline Curve Smoother. Take every point and its neighbor points on the curve, generate two vectors and . Make the second point B to be the midpoint Read more…